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The TEL focus ring designated BSP 305-70-T7.5 is a wafer-edge consumable that sits in the upper region of the electrostatic chuck assembly inside a Tokyo Electron 300 mm plasma etch chamber. It encircles the 300 mm wafer (the “305” family nomenclature reflects this 300 mm wafer class) and forms the immediate ring of material that surrounds the silicon edge during processing. The “T7.5” designation reflects the nominal ring thickness of approximately 7.5 mm, a dimension that is critical because the vertical relationship between the ring top surface and the wafer surface directly shapes the plasma sheath at the wafer perimeter.
In a plasma etch process, the focus ring is one of the most influential and most heavily consumed parts in the chamber. It extends the wafer surface electrically and geometrically so that the plasma sheath, ion trajectories and electric field do not simply collapse at the physical edge of the wafer. Without a correctly profiled and correctly conditioned focus ring, the outermost dice on the wafer experience tilted ion bombardment, altered etch rates and degraded critical dimension control. The BSP 305-70-T7.5 is therefore not a passive spacer; it is an active element of the plasma confinement and edge-uniformity strategy of the tool.
As a consumable exposed continuously to energetic ion bombardment, fluorine- and chlorine-bearing chemistries and elevated surface temperatures, this ring erodes predictably over its service life. Maintaining a stock of qualified, dimensionally accurate focus rings keeps a 300 mm etch fleet inside its edge-yield window, which is exactly the role this 2nd-source new part is intended to fill.
The focus ring performs several simultaneous functions, all of which converge on one objective: making the plasma behave the same way at the wafer edge as it does across the wafer centre. Its key roles include:
Focus rings of this class are manufactured from high-purity materials chosen to withstand aggressive plasma chemistries while contributing minimal particle and metallic contamination. The grade, purity and surface finish of the ring directly determine both its etch lifetime and its effect on wafer yield.
Depending on the specific process recipe the BSP 305-70-T7.5 supports, focus rings in this position are typically produced from high-purity silicon, quartz or a fine-grained ceramic. The material is selected so that, as it erodes, any sputtered species are compatible with the wafer chemistry rather than introducing harmful metallic or particulate contamination.
The ring must survive continuous exposure to reactive ion etching conditions, including fluorine- and chlorine-based chemistries, high RF power densities and substantial thermal cycling between idle and process states.
Because the focus ring governs conditions at the wafer perimeter, its state has a direct and measurable effect on device yield and tool availability. The consequences of using a worn, contaminated or out-of-specification ring include:
The dominant wear mode is gradual erosion of the ring top surface under ion bombardment. As the 7.5 mm thickness reduces, the step height between ring and wafer increases, the plasma sheath bends downward at the edge and edge process results drift. This is a normal end-of-life condition and is the primary reason the part is treated as a scheduled consumable.
Thermal shock, mechanical mishandling during installation, or stress concentrations from uneven seating can crack or chip the ring. Fragments become a direct particle source and can also disturb wafer placement, making any cracked ring an immediate cause for replacement.
Over time the ring surface can roughen or accumulate polymer and etch by-product deposits. Roughened or coated surfaces shed particles, alter local electrical behaviour and change the erosion pattern, all of which degrade edge uniformity and raise defect rates before the ring reaches its nominal thickness limit.
Focus ring replacement is a routine preventive-maintenance task on TEL etch chambers, but it must be performed cleanly and precisely because the ring sets the edge process geometry. A typical replacement sequence follows these steps:
Focus rings are high-frequency consumables, so a reliable supply at predictable cost is central to keeping an etch fleet productive. ESCT Fab Support supplies the ES7099-177 focus ring as a 2nd-source new part with the following advantages:
It surrounds the 300 mm wafer inside a TEL plasma etch chamber and shapes the plasma sheath, ion trajectory and electric field at the wafer edge so that the outermost dice etch with the same critical dimensions and profile as the wafer centre.
No. This is a 2nd-source new part supplied by ESCT Fab Support. It is a new, unused component manufactured to be compatible with TEL P/N 2L10-252512-11 and verified to original form, fit and function, but it is not an original OEM part and is not sold as one.
It refers to the nominal ring thickness of approximately 7.5 mm. This thickness, together with the inner diameter, sets the step height between the ring top and the wafer surface, which is one of the most important factors in edge sheath shaping and etch uniformity.
Replacement interval depends on the process recipe, RF power and run-rate, so it is driven by accumulated process time or a measured edge-performance limit rather than a fixed calendar date. Most fabs replace focus rings on a defined preventive-maintenance schedule, which is why qualified spares are worth holding.
Typical indicators are measurable thickness loss, edge critical-dimension drift, tilted profiles on outer dice, rising particle counts, or visible cracking, chipping or surface roughening. Any of these conditions warrants replacement to protect edge yield.
The standard lead time is 4-5 weeks. Planning replacements around this window allows fabs to maintain adequate buffer stock and avoid unplanned downtime caused by a depleted consumable.
The TEL focus ring BSP 305-70-T7.5 (OEM P/N 2L10-252512-11, ESCT P/N ES7099-177) is a critical wafer-edge consumable in Tokyo Electron 300 mm plasma etch chambers. By shaping the plasma sheath, controlling ion incidence angle and managing RF coupling at the wafer perimeter, it protects edge critical-dimension control, etch uniformity and particle performance. As a high-purity, dimensionally accurate 2nd-source new part with a 4-5 week lead time, the ES7099-177 gives fabs a cost-effective and reliable way to keep their etch fleet inside its edge-yield window without depending solely on the OEM supply channel.
Disclaimer: This part is supplied by ESCT Fab Support as a new, OEM-compatible second-source component, verified to the form, fit and function of Tokyo Electron part number 2L10-252512-11. It is not an original OEM part and is not sold as one. It is not manufactured by, endorsed by, or affiliated with Tokyo Electron, and all manufacturer names and part numbers are quoted for identification and compatibility purposes only.
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